Roaming encoded information reading terminal

ABSTRACT

A portable encoded information reading (EIR) terminal for incorporation in a data collection system having a host computer, a plurality of peer EIR terminals, and a plurality of interconnected networks including one or more wireless networks, can comprise a central processing unit (CPU), a memory, an encoded information reading (EIR) device configured to output raw message data containing an encoded message or decoded message data corresponding to an encoded message, and at least one wireless communication interface. The EIR terminal can provide IEEE 802.11-conformant wireless distribution system services, including association, disassociation, distribution, integration, and re-association, to the peer EIR terminals. The EIR terminal can be associated with a home network and have a home address belonging to the address range associated with the home network.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit of U.S. patent applicationSer. No. 13/470,510 for a Roaming Encoded Information Reading Terminal,filed May 14, 2012 (and published Nov. 15, 2012 as U.S. PatentApplication Publication No. 2012/0287910), now U.S. Pat. No. 8,611,309,which is a division of U.S. patent application Ser. No. 12/070,895 for aRoaming Encoded Information Reading Terminal, filed Feb. 21, 2008 (andpublished Aug. 27, 2009 as U.S. Patent Publication No. 2009/0213811),now U.S. Pat. No. 8,179,859. Each of the foregoing patent applications,patent publications, and patents is hereby incorporated by reference inits entirety.

FIELD OF THE INVENTION

The invention is generally related to data collection systems employingencoded information reading (EIR) terminals and is specifically relatedto a system and method of data communication in a data collection systememploying EIR terminals.

BACKGROUND

Encoded information reading (EIR) terminals equipped with wirelesscommunication interfaces are widely used in retail stores, shippingfacilities, etc. The protocol most widely used for providing datacommunications within the data collection system employing EIR terminalsis Internet Protocol (IP) version 4. The routing scheme of IPv4determines the destination network information from the destination IPaddress of a datagram. This can be analogized to the “old” phonenumbering scheme (which became out-of-dated with the introduction ofphone number portability), where an area code and a three-digit prefixdetermined the geographical location of the land-line phone. Whenever aland-line phone subscriber moved from a geographical zone served by onelocal exchange to a geographical zone served by another local exchange,the subscriber's phone number would change to satisfy the area code andlocal exchange-based numbering scheme. An IPv4 address consists ofnetwork address bits and host address bits, as defined by a netmask.Continuing the analogy, the network address bits can be consideredplaying the role of the area code and local exchange part of the phonenumber. Hence, whenever a networked device moves out of the zone servedby the network defined by the network address bits of the device's IPaddress, the device must change its IP address, since IPv4 routing wouldnot work and IP datagrams to the device would not be delivered if thedevice is connected to a network whose network address is different fromthe network part of the device's IP address.

The requirement of changing the IP address by a roaming device is not ofa great concern unless the device, e.g., an EIR terminal equipped with awireless network interface, moves from one network to another while atleast one communication session (e.g., a TCP connection) in which theterminal participates, is active: the TCP connection would be lostimmediately upon the terminal changing its IP address.

Accordingly, there is a need for a method of keeping the activecommunication session alive while a wireless networked device, e.g., anEIR terminal, is roaming from one network to another.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 illustrates a network-level view of an embodiment of a datacollection system employing EIR terminals according to the invention.

FIG. 2 illustrates an exemplary embodiment of the mobility binding tablestructure according to the invention.

FIG. 3 illustrates an exemplary embodiment of IP datagram encapsulation.

FIGS. 4 a-4 b illustrate exemplary embodiments of the visitor liststructure according to the invention.

FIG. 5 a illustrates a network-level view of an alternative embodimentof a data collection system employing EIR terminals according to theinvention.

FIG. 5 b illustrates a structure of a network address translation (NAT)table according to the invention.

FIG. 6 illustrates a sequence of disassociation and association requestsby a roaming EIR terminal, and corresponding disassociation andassociation responses by wireless access points or portals.

FIG. 7 illustrates a component diagram of an EIR terminal according tothe invention.

FIGS. 8 a and 8 b illustrate an exemplary hand held EIR terminalhousing.

FIGS. 9 a-9 c illustrate an exemplary portable and remountable EIRterminal housing.

FIG. 10 a illustrates a first exemplary deployment of an EIR terminalaccording to the invention within a retail store.

FIG. 10 b illustrates a second exemplary deployment of an EIR terminalaccording to the invention within a retail store.

FIGS. 10 c and 10 d illustrate PIN and signature data entry operationalmodes of an EIR terminal according to the invention.

The drawings are not necessarily to scale, emphasis instead generallybeing placed upon illustrating the principles of the invention. In thedrawings, like numerals are used to indicate like parts throughout thevarious views.

DETAILED DESCRIPTION

There is provided a portable encoded information reading (EIR) terminalfor incorporation in a data collection system. The data collectionsystem, schematically shown in FIG. 1, can include a plurality of EIRterminals 100 a-100 z in communication with a plurality ofinterconnected networks 110 a-110 z. In one aspect, one of the networks110 a-110 z can be connected to the Internet 190. In another aspect, oneor more networks of the plurality of networks 110 a-110 z can act as anOSI layer 2 network implementing IEEE 802.2 Logical Link Control, i.e.,can appear to be functionally equivalent to a broadcast Ethernet-basedLAN from the perspective of other networks and higher level protocols.The plurality of networks 110 a-110 z can include at least one IEEE802.11-conformant wireless network

In one aspect, the networks 110 a-110 z can be interconnected via one ormore one or more routers 150 a-150 z. In another aspect, a router can beprovided by a wireless portal routing datagrams between a wireless and anon-wireless network, e.g., wireless portal 140 a in FIG. 1. In afurther aspect, a wireless portal can be collocated with a wirelessaccess point (AP).

In another aspect, an EIR terminal can establish one or more wirelesslinks with one or more peer EIR terminals, with a wireless AP, or with awireless portal. The EIR terminal can provide IEEE 802.11-conformantwireless distribution system services, including association,disassociation, distribution, integration, and re-association, to thepeer EIR terminals, thus acting as a wireless mesh access point (MAP) ora wireless mesh point portal (MPP).

In another aspect, a wireless AP or portal can be provided, e.g., by aninfrastructure AP or portal, or by a mesh point terminal providing IEEE802.11-conformant wireless distribution system services to its peer EIRterminals.

While different networks are designated herein, it is recognized that asingle network as seen from the network layer of the Open SystemInterconnection (OSI) model can comprise a plurality of lower layernetworks, e.g., what can be regarded as a single Internet Protocol (IP)network, can include a plurality of different physical networks.

In a further aspect, the data collection system can further include arouter 150 k routing datagrams between the networks 110 a-110 z and atleast one host computer 171. In one embodiment, the host computer 171can host a retail store inventory database including, e.g., a productinformation table, a pricing table, and an inventory table. In anotherembodiment, the host computer 171 can host a shipment databaseincluding, e.g., an item tracking table. A skilled artisan wouldappreciate the fact that other applications running on the host computerare within the scope and spirit of the invention.

An EIR terminal 100 c can establish a communication session with thehost computer 171. In one embodiment, the communications between the EIRterminal 100 c and the host computer 171 can comprise a series of HTTPrequests and responses transmitted over one or more TCP connections,although a person skilled in the art would appreciate the fact thatusing other transport and application level protocols is within thescope and the spirit of the invention. In one aspect, at least one ofthe messages transmitted by the EIR terminal can include decoded messagedata corresponding to, e.g., a bar code label or an RFID label attachedto a product or to a shipment item. For example, an EIR terminal cantransmit a request to the host computer to retrieve product informationcorresponding to a product identifier encoded by a bar code labelattached to the product, or to transmit an item tacking record for anitem identified by a bar code label attached to the product.

Under the teachings of the prior art, if the EIR terminal 100 wasphysically moved (e.g., by the terminal operator) from the wirelesstransmission range of the wireless AP or portal 140 a into the wirelesstransmission range of the wireless AP or portal 140 b, the EIR terminalwould have to change its IP address upon associating with the newwireless AP or portal 140 b, and hence all the existing communicationsessions (e.g., TCP connections in an IP network) with the host computer171 would be terminated, since the datagrams addressed to the old IPaddress would not reach the EIR terminal.

In accordance with the one embodiment of the invention, the EIR terminal110 always keeps its permanent IP address, so that the EIR terminal 110can maintain all the active communication sessions using the permanentIP address when roaming between the networks 110 a-110 z. In order tocontinue to receive datagrams routed in accordance with the IPv4 routingalgorithm, the EIR terminal can be associated with a temporary IPaddress to which datagrams can be delivered using conventional IPv4routing. A router having an interface on the network identified by thenetwork part of the permanent IP address can be notified of thetemporary IP address of the roaming EIR terminal, so that the routerwould be able to forward to the terminal the datagrams addressed to thepermanent IP address.

In one aspect, the functionality related to using a temporary IP addresscan be implemented in accordance with RFC 3344 by Network Working Group.

An EIR terminal can have a home network whose address space can includethe terminal's permanent IP address. The permanent IP address can bealso referred to as a home address. In one aspect, the home network canbe identified by the network part of the terminal's permanent IPaddress.

In one embodiment, the home network can be provided by a wirelessnetwork, e.g., the wireless network 110 a can be a home network for theEIR terminal 100 a, as shown in FIG. 1. In another embodiment, the homenetwork can be provided by a wired network, e.g., the wired network 110k can be a home network for the EIR terminal 100 z which can connect tothe network 110 k via a docking station 133. Any network of the datacollection system which is different from an EIR terminal's homenetwork, is referred to as a foreign network. While being connected to aforeign network, the EIR terminal can be associated with a temporary IPaddress, also referred to as a care-of address.

For example, for the EIR terminal 100 a of FIG. 1, the wireless network110 a can be the home network, and the wireless network 110 b can be aforeign network if the EIR terminal is physically moved within thewireless transmission range and is associated with the wireless AP orportal 140 b. For the EIR terminal 100 z of FIG. 1, the wired network110 k can be the home network, and the wireless network 110 a or 110 bcan be a foreign network if the EIR terminal is physically moved withinthe wireless transmission range and is associated with the respectivewireless AP or portal 140 a or 140 b.

In one embodiment, a home address can be permanently assigned to an EIRterminal using a manual or an automated procedure. In anotherembodiment, a home address can be assigned to an EIR terminal usingDynamic Host Configuration Protocol (DHCP) upon the EIR terminalassociation with the home network. A skilled artisan would appreciatethe fact that other ways of assigning the home address to an EIRterminal are within the scope and the spirit of the invention.

The data collection system can include one or more mobility agents,including home agents and foreign agents, which facilitate the EIRterminal roaming functionality. An EIR terminal can be associated with ahome agent. The home agent functionality can be provided by a routerhaving an interface on the EIR terminal's home network. For example, anEIR terminal 110 a can be associated with a home agent provided by thewireless AP or portal 140 a.

In one aspect, a home agent can maintain current location informationfor a roaming EIR terminal. In one embodiment, a home agent can maintaina mobility binding table. The mobility binding table 200 can have astructure shown in FIG. 2 and can contain a plurality of mobilitybinding entries. A mobility binding entry can contain a home address 210and a care-of address 220 of a roaming EIR terminal. A skilled artisanwould appreciate the fact that other fields can be included in thestructure of a mobility binding entry.

In another aspect, a home agent can be adapted to forward IP datagramsaddressed to a roaming EIR terminal's home address, so that thedatagrams would be delivered to the roaming EIR terminal via a routerhaving an interface on a foreign network. In one embodiment, the homeagent can be adapted to perform tunneling of the IP datagrams addressedto a roaming EIR terminal, by encapsulating each IP datagram into a newIP datagram as shown in FIG. 3. The IP destination field 310 of the newIP datagram 300 can contain the care-of address of the roaming EIRterminal. The original IP datagram 301 can be put into the payload part320 of the new IP datagram 300. A skilled artisan would appreciate thefact that other ways of tunneling IP datagrams to a roaming EIR terminalby a home agent are within the scope and the spirit of the invention.

On a foreign network, the routing services to a roaming EIR terminal canbe provided by a foreign agent. The foreign agent can be provided by arouter having an interface on a network visited by an EIR terminal.

When the EIR terminal determines that it has just moved to a new foreignnetwork, it can acquire a new care-of address. In one embodiment, an EIRterminal can get associated with a care-of address advertised by aforeign agent. In another embodiment, an EIR terminal can acquire acare-of address via an external address assignment mechanism (e.g.,DHCP; a skilled artisan would appreciate the fact that other IP addressassignment mechanisms are within the scope and the spirit of theinvention) and associate the acquired care-of address with one of theterminal's network interfaces (e.g., by establishing an IP alias) inorder to be able to receive datagrams addressed to the care-of address.The care-of address acquired by an EIR terminal via an external addressassignment mechanism is referred to as a co-located IP address.

In one embodiment, the foreign agent can be adapted to receive thetunneled datagrams addressed to the care-of address, de-capsulate theoriginal IP datagrams, look up the roaming EIR terminal by its homeaddress in a visitor list maintained by the foreign agent, and forwardthem to the roaming EIR terminal using an OSI layer 2 deliverymechanism. In one embodiment, the visitor list 400 can have a structureshown in FIG. 4 a and can contain a plurality of visitor list entries. Avisitor entry can contain a home address 410, a home agent address 420,and a MAC address 430 of a roaming EIR terminal associated with theforeign agent. In another embodiment, the visitor list entry can have astructure shown in FIG. 4 b and can include a co-located care-of address440, a home agent address 420, and a MAC address 430 of a roaming EIRterminal associated with the foreign agent. A skilled artisan wouldappreciate the fact that other fields can be included in the structureof a visitor list entry.

In another aspect, the foreign agent can act as a default router for theroaming EIR terminal, so that the EIR terminal would transmit outgoingIP datagrams to the foreign agent for forwarding to the respectivedestinations.

A mobility agent can advertise its presence on a network by periodicallytransmitting to a broadcast or a multicast address an agentadvertisement message. The agent advertisement message can contain aflag indicating whether the mobility agent transmitting the message ishome or foreign agent. In one embodiment, an agent advertisement messagetransmitted by a foreign agent can contain one or more care-ofaddresses.

In another aspect, an EIR terminal, instead of waiting for an agentadvertisement broadcast, can transmit an agent solicitation messagewhich can be responded to by a mobility agent.

In a further aspect, an EIR terminal can determine, e.g., from an agentadvertisement message that it is has just moved to another network. Askilled artisan would appreciate the fact that other ways of detecting anew network by an EIR terminal, e.g., by associating with a wireless APor wireless portal, are within the scope and the spirit of theinvention.

An EIR roaming on a foreign network can register its care-of addresswith its home agent by transmitting a registration request message,either directly to the home agent or via a foreign agent. Theregistration request message can include the terminal's home address,the home agent address, and the care-of address. A skilled artisan wouldappreciate the fact that the registration request message can furtherinclude other fields. The home agent, upon receiving a registrationrequest message, can add a new entry to its mobility binding table.

In one embodiment, the registration request message can contain anauthentication extension for authenticating a roaming EIR terminal toits home agent in order to prevent a malicious party from posing as theEIR terminal and thus attempting to intercept IP datagrams intended tobe delivered to the EIR terminal. In one aspect, the authenticationextension can contain a Security Parameter Index (SPI) followed by anauthenticator. The SPI can contain an identifier of an algorithm (e.g.,MD5) used to encrypt the authenticator. In another aspect, theauthentication extension can further contain one or more unique dataitems designed to prevent recording and re-play by a malicious party ofa valid message exchange between a roaming EIR terminal and its homeagent. The unique data items can be generated using timestamps, orrandomly generated numbers. A skilled artisan would appreciate the factthat other ways of authenticating a roaming EIR terminal to its homeagent, and preventing message recording and re-play are within thespirit and the scope of the invention.

The home agent can be adapted to intercept the datagrams sent to the EIRterminal's home address and forward the IP datagrams to the care-ofaddress via IP encapsulation described herein supra. In a foreign agentcare-of address embodiment, the IP datagrams addressed to the care-ofaddress can be received by the foreign agent, which can de-capsulate theoriginal IP datagrams and forward them to the roaming EIR terminal usingan OSI layer 2 delivery mechanism. In a co-located care-of addressembodiment, the IP datagrams addressed to the care-of address can bereceived by the EIR terminal itself, which then can perform thede-capsulation of the original IP datagrams.

In another aspect, the wireless AP or portal 140 a providing home agentservices for a roaming EIR terminal 100 a, can be adapted to maintain inits memory a roaming buffer which can be used to buffer MAC frames thatcannot be delivered to, or have not been acknowledged by the destinationEIR terminal. In one embodiment, the EIR terminals 100 a-100 z and thewireless APs or portals 140 a-140 z can be IEEE 802.11-conformant, whichrequires a destination EIR to acknowledge at the physical layer unicastdata and control MAC frames. A skilled artisan would appreciate the factthat other types of MAC frame acknowledgements by a destination EIRterminal are within the scope and the spirit of the invention.

In one embodiment, the roaming buffer implemented by a wireless AP orportal providing home agent services for a roaming EIR terminal canextend the functionality of an IEEE 802.11-conformant power save buffer.

The wireless AP providing home agent services for a roaming EIR terminalor portal can start buffering MAC frames responsive to:

(a) receiving a notification from the destination EIR terminal that theEIR terminal is entering power save mode;

(b) receiving a disassociation request from the destination EIRterminal; or

(c) not receiving, within a pre-defined timeout, an acknowledgement fromthe destination EIR terminal responsive to transmitting a unicast dataor control MAC frame to the EIR terminal.

The wireless AP or portal providing home agent services for a roamingEIR terminal can forward one or more buffered MAC frames to thedestination EIR terminal responsive to:

(a) receiving a power save poll frame from the destination EIR terminalindicating that the EIR terminal is ready to receive any frames whichhave been buffered by the AP or portal while the terminal was in thepower save mode;

(b) receiving a re-association request from the destination EIRterminal;

(c) receiving from the destination EIR terminal an acknowledgement for apreviously transmitted unicast data or control MAC frame; or

(d) receiving from the destination EIR terminal a registration requestmessage.

A skilled artisan would appreciate the fact that other types of eventstriggering initiating the frame buffering and forwarding buffered framesby a wireless AP or portal are within the scope and the spirit of theinvention.

In another embodiment, shown in FIG. 5 a, the gateway router 150 kcapable of routing IP datagrams between a remote host computer 171 andEIR terminals in communication with local networks 110 a-110 z, can beadapted to perform network address translation (NAT) on the datagramsrouted to and from EIR terminals 100 a-100 z, by re-writing destinationIP addresses and/or port numbers in the datagrams addressed to the EIRterminals 100 a-100 z, and re-writing source IP addresses and/or portnumbers in the datagrams originated by the EIR terminals 100 a-100 z, sothat a remote host computer 171 would be able to communicate to aroaming EIR terminal using the same IP address even when the EIRterminal roams between the networks 110 a-110 z and changes its IPaddress accordingly. Another important advantage afforded by using arouter configured to perform NAT in accordance with the invention isproviding correct routing of datagrams to and from EIR terminals roamingbetween the networks 110 a-110 z in a situation when the address spacesof two or more local networks 110 a-110 z partially or even fullyoverlap.

The gateway router 150 k can maintain a NAT table 510 containing a NATentry for every EIR terminal. The gateway router 150 k can create a newNAT entry upon receiving a registration request message from a roamingEIR terminal.

A NAT table entry can comprise at least some of the fields shown in FIG.5 b, including an external IP address 512 and an internal IP address 514of an EIR terminal identified by the EIR terminal identifier 511. In oneembodiment, the terminal identifier can be provided, e.g., by theterminal serial number, or by a MAC address of one of the terminal'snetwork interfaces. In another embodiment, the terminal identifier canbe provided by the terminal home address, which can be associated withthe terminal's home network. In a further embodiment, the terminalidentifier can be provided by the combination of the terminal homeaddress and the home network identifier. In one aspect, the home networkidentifier can be provided, e.g., by the network's Service SetIdentifier (SSID). A skilled artisan would appreciate the fact thatother fields can be included in the structure of a NAT entry.

The external IP address can be used by any computer in communicationwith the gateway router 150 k (e.g., by the host computer 171, or by apeer EIR terminal) to communicate with an EIR terminal connected to oneof the networks 110 a, 100 b. The external IP address can belong to anaddress range associated with the network 110 z on which the router 150k has at least one interface, The internal IP address can belong to anaddress range associated with one of the local networks 110 a-110 b,e.g., by having the network part matching the network prefix of one ofthe local networks 110 a-110 b, by having the network part matching thenetwork prefix of the network 110 z on which the router 150 k has atleast one interface. The internal IP address can belong to an addressrange associated with one of the local networks 110 a-110 b, e.g., byhaving the network part matching the network prefix of one of the localnetworks 110 a-110 b. Gateway router 150 k can be adapted to interceptIP datagrams addressed to and originated by the EIR terminals 110 a-110z, and perform network address translation including the steps ofexecuting a NAT table lookup and re-writing the destination IP addressfield of the IP datagrams addressed to the EIR terminal by replacing theterminal's external IP address with the corresponding internal IPaddress found in the NAT table, and re-writing the source IP addressfield of the IP datagrams originated by the EIR terminal by replacingthe terminal's internal IP address with the corresponding external IPaddress found in the NAT table.

A roaming EIR terminal can be adapted to acquire (e.g., via DHCP) a newinternal IP address upon associating with one of the networks 110 a-110b. In one embodiment, the EIR terminal can transmit to the gatewayrouter 150 k a registration request message containing the newlyacquired IP address and a terminal identifier.

Upon receiving the registration request message, the gateway router 150k can be programmed to create a NAT entry corresponding to the EIRterminal which transmitted the registration request message, to reflectthe new internal IP address of an EIR terminal identified by theterminal identifier contained in the registration request message.

Since the external IP address of a roaming EIR terminal does not change,the EIR terminal 110 can maintain all the active communication sessionsusing the external IP address when roaming between the networks 110a-110 z.

In another embodiment, one external IP address can be used to route IPdatagrams to and from one or more EIR terminals. This can be achieved byassigning one or more TCP/UDP port numbers to each EIR terminal incommunication with one of the networks 110 a-110 z. A NAT table entryfor an EIR terminal identified by the EIR terminal identifier 511 caninclude an external IP address 512, an external TCP/UDP port 516 port,and an internal IP address 514 of the EIR terminal. If more than oneTCP/UDP port is needed for an EIR terminal, then the NAT table entry canfurther include the internal TCP/UDP port field 518. A skilled artisanwould appreciate the fact that other fields can be included in thestructure of a NAT entry.

In one embodiment, the address spaces of two or more local networks 110a-110 z can partially or fully overlap. For example, two or more localnetworks 110 a-110 z can use the same private internet address spacedefined in RFC 1918 by Network Working Group. To provide for networklayer connectivity outside the respective local network 110 a-110 b,local routers 140 a-140 b can be adapted to perform NAT and translateeach EIR terminal internal IP address belonging to a local network'saddress space to an external IP address belonging to the address spaceof the network 110 z interconnecting the routers 140 a-140 b and thegateway router 150 k. The address space of the network 110 z can beprovided by a public internet address range or a private internetaddress range defined in RFC 1918. Gateway router 150 k can be adaptedto perform NAT by translating the network's 110 z addresses into publicIP addresses, thus providing for correct datagram delivery between aroaming EIR terminal and a remote host computer 171.

Since the address spaces of two or more local networks 110 a-110 z canoverlap, and since the terminal MAC address would not be found in adatagram delivered from a terminal 100 a-100 z via a router 140 a-140 bto the gateway router 150 k, in order for the gateway router 150 k tocreate a new NAT entry for an EIR terminal roaming from a home networkto a foreign network, the EIR terminal can transmit to the gatewayrouter 150 k a registration request message containing the newlyacquired internal IP address, the foreign network identifier, and aterminal identifier. The terminal identifier can be provided, e.g., bythe terminal's serial number, or by a MAC address of one of the terminalnetwork interfaces. In another embodiment, the terminal identifier canbe provided by the combination of the terminal home address and the homenetwork identifier. In one aspect, the home network identifier can beprovided, e.g., by the network's Service Set Identifier (SSID).

In another aspect, the gateway router 150 k providing NAT services for aroaming EIR terminal 100 a, can be adapted to maintain in its memory aroaming buffer which can be used to buffer TCP packets addressed by anexternal TCP server to an EIR terminal having a NAT entry in the NATtable maintained by the gateway router. The receiving EIR terminal cantransmit one or more TCP packets back to the external TCP server. Inaccordance with TCP protocol defined by RFC 793 by Network WorkingGroup, any TCP packet contains an acknowledgement field containing thesequence number of the last data byte successfully received by thepacket sender. The gateway router can analyze TCP packets initiated bythe EIR terminal and remove from the buffer the TCP packets which havebeen acknowledged by the EIR terminal. The gateway router can forwardzero or more buffered TCP packets to the destination EIR terminalresponsive to receiving a registration request message from thedestination EIR terminal.

A skilled artisan would appreciate the fact that other network andtransport layer protocols with acknowledgments are within the scope andthe spirit of the invention.

Data-link layer (OSI layer 2) behavior of a roaming EIR terminal is nowbeing described with references to FIG. 6. In one aspect, an EIRterminal 100 which is being physically moved (e.g., by the terminaloperator) from the wireless transmission range of the wireless AP orportal 140 a in communication with the network 110 a into the wirelesstransmission range of the wireless AP or portal 140 b in communicationwith the network 110 b, can determine whether it is necessary toinitiate a roaming procedure by ascertaining whether one or more of thefollowing roaming conditions has been satisfied:

a. receive signal strength indication (RSSI) from the wireless AP orportal the EIR terminal is currently associated with, being too low;

b. difference between RSSI of the wireless AP or portal the EIR terminalis currently associated with and another wireless AP or portal beinglarger than a pre-defined threshold;

c. excessive interference or noise in the network the EIR terminal iscurrently associated with;

d. excessive number of unsuccessful attempts to re-associate with thewireless AP or portal the EIR terminal is currently associated with;

e. insufficient capacity of the wireless AP or portal the EIR terminalis currently associated with; or

f. transmission errors exceeding a pre-defined threshold.

A skilled artisan would appreciate the fact that other types of eventstriggering a roaming procedure initiation by an EIR terminal are withinthe scope and the spirit of the invention.

In another aspect, a wireless AP or portal can be provided, e.g., by aninfrastructure AP or portal, or by a mesh point terminal providing IEEE802.11-conformant wireless distribution system services to its peer EIRterminals.

In a further aspect, responsive to determining that a roaming procedureneeds to be initiated, the roaming EIR terminal can disassociate withthe current wireless AP or portal, by sending a Disassociate request610, to which the current wireless AP or portal can reply by sending aDisassociate response 620. Upon disassociating with the current wirelessAP or portal, the EIR terminal can send an Associate request 630 toanother wireless AP or portal. The association procedure can becompleted by the wireless AP or portal replying with an Associateresponse 640.

In a further aspect, the association procedure can be followed by theEIR terminal authenticating with the new wireless AP or portal, and/orexchanging encryption keys.

Now referring to attributes of EIR terminal 100 in further reference toFIG. 7, an EIR terminal 100 according to the invention can comprise acentral processing unit (CPU) 251 and a memory 252, both coupled to asystem bus 259. In one embodiment, the CPU 251 can be provided by ageneral purpose microprocessor. The EIR terminal 100 can furthercomprise one or more encoded information reading (EIR) devices 253,including a bar code reading device, an RFID reading device, and a cardreading device, also coupled to the system bus 259. In one embodiment,an EIR reading device can be capable of outputting decoded message datacorresponding to an encoded message. In another embodiment, the EIRreading device can output raw message data containing an encodedmessage, e.g., raw image data or raw RFID data, to be processed by theCPU 251. The EIR terminal module 100 can further comprise a keyboardinterface 254 and a display adapter 255, both also coupled to the systembus 259. The EIR terminal 100 can further comprise one or more wirelesscommunication interfaces 256, also coupled to the system bus 259. TheEIR terminal 100 can further comprise a battery 260.

Form factors and housings for the EIR terminal according to theinvention are now being described. The components of EIR terminal 100can be incorporated into a variety of different housings. As indicatedby the embodiment of FIGS. 8 a and 8 b, the components of FIG. 7 can beincorporated into a hand held housing 101. EIR terminal 100 of FIGS. 8 aand 8 b is in the form factor of a hand held portable data terminal EIRterminal 100 as shown in FIGS. 8 a and 8 b includes a keyboard 1090, adisplay 504 having an associated touch screen overlay, a card reader1348, and an imaging module 360 which includes the components of imagingassembly as described herein; namely, image sensor array incorporated onan image sensor IC chip. Imaging module 360 has an associated imagingaxis, a_(i). As indicated by the side view of FIG. 8 b, the componentsof the block diagram of FIG. 7 may be supported within housing 101 on aplurality of circuit boards 1077. Imaging module 360 may include animage sensor array having color sensitive pixels as described inProvisional Patent Application Nos. 60/687,606, filed Jun. 3, 2005,60/690,268, filed Jun. 14, 2005, 60/692,890, filed Jun. 22, 2005, and60/694,371, filed Jun. 27, 2005, all of which are entitled DigitalPicture Taking Optical Reader Having Hybrid Monochrome And Color ImageSensor, and all of which are incorporated herein by reference.

In the embodiment of FIGS. 9 a-9 c, the EIR terminal 100 is in the formof a transaction terminal which may be configured as a retail purchasetransaction terminal or as a price verifier. Housing 102 of thetransaction terminal shown in FIGS. 9 a-9 c is configured to be portableso that it can be moved from location to location and is furtherconfigured to be replaceably mounted on a fixed structure such as afixed structure of a cashier station or a fixed structure of the retailstore floor (e.g., a shelf, a column 264 best viewed in FIG. 10 b).Referring to bottom view of FIG. 9 c, the housing 102 of the EIRterminal 100 has formations 268 facilitating the replaceable mounting ofEIR terminal 100 on a fixed structure. Referring now to FIG. 9 b, EIRterminal 100 includes a display 504 having an associated touch screen504T, a card reader 1348, an imaging module 360, and a luminous shroud362. When light from the illumination block (not shown in FIG. 8)strikes luminous shroud 362, the shroud glows to attract attention tothe location of imaging assembly. In certain operating modes asindicated in FIG. 10 c, the EIR terminal 100 in accordance with any ofFIGS. 9 a-9 c, displays on display 504 a PIN entry screen prompting acustomer to enter PIN information into touch screen 504T. In otheroperating modes, as indicated in FIG. 10 d, the EIR terminal 100displays on display 504 a signature prompt screen prompting a customerto enter signature information into the device with use of a stylus 505.

Referring to FIGS. 10 a and 10 b, various installation configurationsfor the EIR terminal of FIGS. 9 a-9 c are shown. In the view of FIG. 10a, the EIR terminal 100 is installed as a retail purchase transactionterminal at a point of sale cashier station. In the setup of FIG. 10 a,the EIR terminal 100 is configured as a retail purchase transactionterminal and is utilized to aid and facilitate retail transactions at apoint of sale. A customer may enter a credit card or a debit card intocard reader 1348 and retail purchase transaction terminal may transmitthe credit card information to credit/debit authorization network.

In the view of FIG. 10 b, the EIR terminal 100 is configured as a priceverifier to aid customers in checking prices of products located on astore floor. EIR terminal 100 may be mounted on a shelf (not shown inFIG. 10 b) or on a column 264 or other fixed structure of the retailstore. EIR terminal 100 may decode bar code data from bar codes on storeproducts and transmit decoded out bar code messages to a store serverfor lookup of price information which is sent back from the store serverto terminal 100 for display on display 504.

While the present invention has been particularly shown and describedwith reference to certain exemplary embodiments, it will be understoodby one skilled in the art that various changes in detail may be affectedtherein without departing from the spirit and scope of the invention asdefined by claims that can be supported by the written description anddrawings. In particular, while the present invention has been describedwith reference to Internet Protocol (IP) networks, it is recognized thatother network addressing schemes and standards are within the scope andthe spirit of the invention.

Further, where exemplary embodiments are described with reference to acertain number of elements it will be understood that the exemplaryembodiments can be practiced utilizing less than the certain number ofelements.

A small sample of systems, apparatuses and methods described herein isas follows:

A1. A portable encoded information reading (EIR) terminal forincorporation in a data collection system having a plurality of peer EIRterminals and a plurality of interconnected networks including one ormore wireless networks, said EIR terminal associated with a home networkhaving an associated address range, said home network being one of saidplurality of networks, said EIR terminal configured to provide IEEE802.11-conformant wireless distribution system services, includingassociation, disassociation, distribution, integration, andre-association, to said peer EIR terminals, said EIR terminalcomprising:

a central processing unit (CPU);

a memory;

an encoded information reading (EIR) device selected from the groupconsisting of: a bar code reading device, an RFID reading device, and acard reading device, said EIR device configured to perform one of:outputting raw message data containing an encoded message, outputtingdecoded message data corresponding to an encoded message;

at least one wireless communication interface;

wherein said EIR terminal is configured, when roaming from a firstnetwork of said plurality of networks to a second network of saidplurality of networks, to maintain zero or more active communicationsessions with at least one remote host computer using a home addressbelonging to said associated address range of said home network; and

wherein said EIR terminal is further configured to receive an agentadvertisement message when in communication with a foreign network otherthan said home network, said agent advertisement message containing oneor more care-of addresses.

A2. The EIR terminal of A1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.A3. The EIR terminal of A1, wherein said EIR terminal is furtherconfigured to transmit an agent solicitation message.A4. The EIR terminal of A1, wherein at least one network of saidplurality of networks is an OSI layer 2 network.A5. The EIR terminal of A1, wherein said home address and said care-ofaddress are Internet Protocol (IP) addresses.A6. The EIR terminal of A1, wherein said first network has at least onefirst network wireless access device selected from the group consistingof: a wireless access point (AP), a wireless portal;

wherein second network has at least one second network wireless accessdevice selected from the group consisting of: a wireless access point(AP), a wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

B1. A portable encoded information reading (EIR) terminal forincorporation in a data collection system having a plurality of peer EIRterminals and a plurality of interconnected networks including one ormore wireless networks, said EIR terminal associated with a home networkhaving an associated address range, said home network being one of saidplurality of networks, said EIR terminal configured to be associatedwith a care-of address when in communication with a foreign networkother than said home network, said EIR terminal configured to provideIEEE 802.11-conformant wireless distribution system services, includingassociation, disassociation, distribution, integration, andre-association, to said peer EIR terminals, said EIR terminalcomprising:

a central processing unit (CPU);

a memory;

an encoded information reading (EIR) device selected from the groupconsisting of: a bar code reading device, an RFID reading device, and acard reading device, said EIR device configured to perform one of:outputting raw message data containing an encoded message, outputtingdecoded message data corresponding to an encoded message;

at least one wireless communication interface;

wherein said EIR terminal is configured, when roaming from a firstnetwork of said plurality of networks to a second network of saidplurality of networks, to maintain zero or more active communicationsessions with at least one remote host computer using a home addressbelonging to said associated address range of said home network; and

wherein said EIR terminal is further configured to transmit aregistration request message to one of: a home agent having a home agentaddress and being in communication with said home network, a foreignagent in communication with said foreign network, said registrationrequest message including said home address, said home agent address,and said care-of address.

B2. The EIR terminal of B1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.B3. The EIR terminal of B1, wherein said registration request messagecontains an authentication extension.B4. The EIR terminal of B1, wherein at least one network of saidplurality of networks is an OSI layer 2 network.B5. The EIR terminal of B1, wherein said home address and said care-ofaddress are Internet Protocol (IP) addresses.B6. The EIR terminal of B1, wherein said first network has at least onefirst network wireless access device selected from the group consistingof: a wireless access point (AP), a wireless portal;

wherein second network has at least one second network wireless accessdevice selected from the group consisting of: a wireless access point(AP), a wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

C1. A portable encoded information reading (EIR) terminal forincorporation in a data collection system having a plurality of peer EIRterminals and a plurality of interconnected networks including one ormore wireless networks, said EIR terminal associated with a home networkhaving an associated address range, said home network being one of saidplurality of networks, said EIR terminal configured to be associatedwith a care-of address when in communication with a foreign networkother than said home network, said EIR terminal configured to provideIEEE 802.11-conformant wireless distribution system services, includingassociation, disassociation, distribution, integration, andre-association, to said peer EIR terminals, said EIR terminalcomprising:

-   -   a central processing unit (CPU);    -   a memory;    -   an encoded information reading (EIR) device selected from the        group consisting of: a bar code reading device, an RFID reading        device, and a card reading device, said EIR device configured to        perform one of: outputting raw message data containing an        encoded message, outputting decoded message data corresponding        to an encoded message;

at least one wireless communication interface;

wherein said EIR terminal is configured, when roaming from a firstnetwork of said plurality of networks to a second network of saidplurality of networks, to maintain zero or more active communicationsessions with at least one remote host computer using a home addressbelonging to said associated address range of said home network; and

wherein said EIR terminal is further configured to receive datagramsaddressed to said care-of address.

C2. The EIR terminal of C1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.C3. The EIR terminal of C1, wherein at least one network of saidplurality of networks is an OSI layer 2 network.C4. The EIR terminal of C1, wherein said home address and said care-ofaddress are Internet Protocol (IP) addresses.C5. The EIR terminal of C1, wherein said first network has at least onefirst network wireless access device selected from the group consistingof: a wireless access point (AP), a wireless portal;

wherein second network has at least one second network wireless accessdevice selected from the group consisting of: a wireless access point(AP), a wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

D1. A data collection system comprising:

a plurality of interconnected networks including one or more wirelessnetworks;

a router configured to route datagrams between said plurality ofnetworks and at least one remote host computer;

a plurality of EIR terminals, each EIR terminal associated with a homenetwork having an associated address range, said home network being oneof said plurality of networks, each EIR terminal comprising a centralprocessing unit (CPU), a memory, at least one wireless communicationinterface, and an encoded information reading (EIR) device selected fromthe group consisting of: a bar code reading device, an RFID readingdevice, and a card reading device, said EIR device configured to performone of: outputting raw message data containing an encoded message,outputting decoded message data corresponding to an encoded message;

wherein at least one EIR terminal of said plurality of EIR terminals isconfigured to provide IEEE 802.11-conformant wireless distributionsystem services, including association, disassociation, distribution,integration, and re-association, to said peer EIR terminals;

wherein said at least one EIR terminal is configured, when roaming froma first network of said plurality of networks to a second network ofsaid plurality of networks, to be associated with a care-of address whenin communication with a foreign network other than said home network,and to maintain zero or more active communication sessions with said atleast one host computer using a home address belonging to saidassociated address range of said home network; and

wherein said at least one EIR terminal is further configured to transmita registration request message to one of: a home agent having a homeagent address and being in communication with said home network, aforeign agent in communication with said foreign network, saidregistration request message including said home address, said homeagent address, and said care-of address.

D2. The data collection system of D1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.D3. The data collection system of D1, wherein said home agent isconfigured to maintain a mobility binding table containing a pluralityof mobility binding entries, each mobility biding entry containing ahome address, and a care-of address of an EIR terminal of said pluralityof EIR terminals.D4. The data collection system of D1, wherein said foreign agent isconfigured to maintain a visitor list containing a plurality of visitorlist entries, each visitor entry containing a home address, a home agentaddress, and a MAC address of an EIR terminal of said plurality of EIRterminals.D5. The data collection system of D1, wherein said foreign agent isconfigured to maintain a visitor list containing a plurality of visitorlist entries, each visitor entry containing a co-located care-ofaddress, a home agent address, and a MAC address of an EIR terminal ofsaid plurality of EIR terminals.D6. The data collection system of D1, wherein said home agent isconfigured to intercept datagrams addressed to said at least one EIRterminal and forward said intercepted datagrams to said care-of address.D7. The data collection system of D1, wherein said foreign agent isconfigured to maintain a visitor list containing a plurality of visitorlist entries, each visitor entry containing a home address, a home agentaddress, and a MAC address of an EIR terminal of said plurality of EIRterminals; and

wherein said foreign agent is configured, upon receiving a datagramaddressed to said care-of address, to retrieve a MAC address of said EIRterminal from said visitor list and forward said datagram to said MACaddress.

D8. The data collection system of D1, wherein at least one network ofsaid plurality of networks is an OSI layer 2 network.

D9. The data collection system of D1, wherein said home address, saidhome agent address, and said care-of address are Internet Protocol (IP)addresses.

D10. The data collection system of D1, wherein said home agent isconfigured to maintain a roaming buffer for buffering MAC framesaddressed to said at least one EIR terminal;

wherein said home agent is further configured to start buffering MACframes addressed to said at least one EIR terminal in said roamingbuffer responsive to a first triggering event; and

wherein said home agent is further configured to forward buffered MACframes addressed to said at least one EIR terminal responsive to asecond triggering event.

D11. The data collection system of D1, wherein said first triggeringevent is selected from the group consisting of: receiving a notificationfrom said at least one EIR terminal that said EIR terminal is entering apower save mode; receiving a disassociation request from said at leastone EIR terminal; and not receiving, within a pre-defined timeout, anacknowledgement from said at least one EIR terminal responsive totransmitting a unicast MAC frame to said at least one EIR terminalD12. The data collection system of D1, wherein said second triggeringevent is selected from the group consisting of: receiving a power savepoll frame from said at least one EIR terminal; receiving are-association request from said at least one EIR terminal; receivingfrom said at least one EIR terminal an acknowledgement for a previouslytransmitted unicast MAC frame; receiving a registration request messagefrom said at least one EIR terminal.D13. The EIR terminal of D1, wherein said first network has at least onefirst network wireless access device selected from the group consistingof: a wireless access point (AP), a wireless portal;

wherein second network has at least one second network wireless accessdevice selected from the group consisting of: a wireless access point(AP), a wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

E1. A data collection system comprising:

a plurality of interconnected networks including one or more wirelessnetworks;

a router configured to route datagrams between said plurality ofnetworks and at least one remote host computer;

a plurality of EIR terminals, each EIR terminal associated with a homenetwork having an associated address range, said home network being oneof said plurality of networks, each EIR terminal comprising a centralprocessing unit (CPU), a memory, at least one wireless communicationinterface, and an encoded information reading (EIR) device selected fromthe group consisting of: a bar code reading device, an RFID readingdevice, and a card reading device, said EIR device configured to performone of: outputting raw message data containing an encoded message,outputting decoded message data corresponding to an encoded message;

wherein said at least one EIR terminal is configured, when roaming froma first network of said plurality of networks to a second network ofsaid plurality of networks, to be associated with a care-of address whenin communication with a foreign network other than said home network,and to maintain zero or more active communication sessions with said atleast one host computer using a home address belonging to saidassociated address range of said home network;

wherein said at least one EIR terminal is further configured to transmita registration request message to one of: a home agent having a homeagent address and being in communication with said home network, aforeign agent in communication with said foreign network, saidregistration request message including said home address, said homeagent address, said care-of address; and

wherein said home agent is configured to maintain a roaming buffer forbuffering MAC frames addressed to said at least one EIR terminal, saidhome agent further configured to start buffering MAC frames addressed tosaid at least one EIR terminal in said roaming buffer responsive to afirst triggering event, said home agent further configured to forwardbuffered MAC frames addressed to said at least one EIR terminalresponsive to a second triggering event.

E2. The data collection system of E1, wherein said first triggeringevent is selected from the group consisting of: receiving a notificationfrom said at least one EIR terminal that said EIR terminal is entering apower save mode; receiving a disassociation request from said at leastone EIR terminal; and not receiving, within a pre-defined timeout, anacknowledgement from said at least one EIR terminal responsive totransmitting a unicast MAC frame to said at least one EIR terminalE3. The data collection system of E1, wherein said second triggeringevent is selected from the group consisting of: receiving a power savepoll frame from said at least one EIR terminal; receiving are-association request from said at least one EIR terminal; receivingfrom said at least one EIR terminal an acknowledgement for a previouslytransmitted unicast MAC frame; receiving a registration request messagefrom said at least one EIR terminal.F1. A data collection system comprising:

a plurality of interconnected networks including one or more wirelessnetworks;

a router configured to route datagrams between said plurality ofnetworks and at least one remote host computer;

a plurality of EIR terminals, each EIR terminal comprising a centralprocessing unit (CPU), a memory, at least one wireless communicationinterface, and an encoded information reading (EIR) device selected fromthe group consisting of: a bar code reading device, an RFID readingdevice, and a card reading device, said EIR device configured to performone of: outputting raw message data containing an encoded message,outputting decoded message data corresponding to an encoded message;

wherein said router is configured to maintain a network addresstranslation (NAT) table, said NAT table comprising at least one NATentry, said at least one NAT entry including an internal addressassociated with an EIR terminal of said plurality of EIR terminals;

wherein said EIR terminal is further configured, when roaming from afirst network of said plurality of networks to a second network of saidplurality of networks, to maintain zero or more active communicationsessions with said at least one host computer using an external address;and

wherein said EIR terminal is configured to acquire a new internaladdress upon associating with a network of said plurality ofinterconnected networks.

F2. The data collection system of F1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.F3. The data collection system of F1, wherein said router is furtherconfigured to intercept at least one datagram originated by said EIRterminal, said at least one datagram including a source address field,said router further configured to re-write said source address fieldwith said external address.F4. The data collection system of F1, wherein said router is furtherconfigured to intercept at least one datagram addressed to said EIRterminal, said at least one datagram including a destination addressfield, said router further configured to re-write said destinationaddress field with said internal address.F5. The data collection system of F1, wherein said EIR terminal has aterminal identifier and is associated with a home network having anassociated address range, and is further associated with a home address,said home network being one of said plurality of networks, said homeaddress belonging to said associated address range of said home network;and

wherein said EIR terminal is further configured to transmit aregistration request message to said router, said registration requestmessage including said terminal identifier and said new internaladdress.

F6. The data collection system of F1, wherein said EIR terminal has aterminal identifier and is associated with a home network having a homenetwork identifier and an associated address range, and is furtherassociated with a home address, said home network being one of saidplurality of networks, said home address belonging to said associatedaddress range of said home network, said terminal identifier provided byone of: said home address, a combination of said home address and saidhome network identifier, a MAC address associated with said at least onewireless communication interface, a serial number of said EIR terminal;and

wherein said EIR terminal is further configured to transmit aregistration request message to said router, said registration requestmessage including said terminal identifier and said new internaladdress.

F7. The data collection system of F1, wherein said at least one NATentry further includes one of: an external address associated with saidEIR terminal, an external port associated with said EIR terminal.

F8. The data collection system of F1, wherein said at least one NATentry further includes an internal port associated with said EIRterminal.

F9. The data collection system of F1, wherein said EIR terminal has aterminal identifier; and wherein said at least one NAT entry furtherincludes said terminal identifier.

F10. The data collection system of F1, wherein said EIR terminal has aterminal identifier and is associated with a home network having a homenetwork identifier and an associated address range, and is furtherassociated with a home address, said home network being one of saidplurality of networks, said home address belonging to said associatedaddress range of said home network, said terminal identifier provided byone of: said home address, a combination of said home address and saidhome network identifier, a MAC address associated with said at least onewireless communication interface, a serial number of said EIR terminal;and

wherein said at least one NAT entry further includes said terminalidentifier.

F11. The data collection system of F1, wherein at least one network ofsaid plurality of networks is an OSI layer 2 network.

F12. The data collection system of F1, wherein said internal address andsaid external address are Internet Protocol (IP) addresses.

F13. The data collection system of F1, wherein at least one EIR terminalof said plurality of EIR terminals is configured to provide IEEE802.11-conformant wireless distribution system services, includingassociation, disassociation, distribution, integration, andre-association, to said peer EIR terminals.F14. The data collection system of F1, wherein said gateway router isfurther configured to maintain a roaming buffer for buffering TCPpackets addressed to said at least one EIR terminal;

wherein said gateway router is further configured to remove one or moreTCP packets from said roaming buffer responsive to said at least one EIRterminal acknowledging receipt of said one or more TCP packets; and

wherein said gateway router is further configured to forward bufferedTCP packets addressed to said at least one EIR terminal responsive toreceiving a registration request message from said at least one EIRterminal.

F15. The data collection system of F1, wherein at least one said localrouter in communication with a local network is configured maintain alocal network address translation (NAT) table, said local NAT tablecomprising at least one local NAT entry, said at least one local NATentry including an internal address associated with an EIR terminal incommunication with said local network.F16. The data collection system of F1, wherein address spaces associatedwith two or more said local networks at least partially overlap.F17. The EIR terminal of F1, wherein said first network has at least onefirst network wireless access device selected from the group consistingof: a wireless access point (AP), a wireless portal;

wherein second network has at least one second network wireless accessdevice selected from the group consisting of: a wireless access point(AP), a wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

G1. A portable encoded information reading (EIR) terminal forincorporation in a data collection system having a plurality of peer EIRterminals and a plurality of interconnected wireless networks, said EIRterminal associated with a home network having an associated addressrange, said home network being one of said plurality of networks, saidEIR terminal comprising:

a central processing unit (CPU);

a memory;

an encoded information reading (EIR) device selected from the groupconsisting of: a bar code reading device, an RFID reading device, and acard reading device, said EIR device configured to perform one of:outputting raw message data containing an encoded message, outputtingdecoded message data corresponding to an encoded message;

at least one wireless communication interface;

wherein said EIR terminal is configured, to maintain zero or more activecommunication sessions with at least one remote host computer whenroaming from a first network of said plurality of networks to a secondnetwork of said plurality of networks, said first network having atleast one first network wireless access device selected from the groupconsisting of: a wireless access point (AP) and a wireless portal, saidsecond network having at least one second network wireless access deviceselected from the group consisting of: a wireless access point (AP) anda wireless portal; and

wherein said EIR terminal is further configured to disassociate withsaid first network and associate with said second network responsive todetection of a roaming process triggering condition selected from thegroup consisting of: receive signal strength indication (RSSI) of saidfirst network wireless access device being too low; difference betweenRSSI of said first network wireless access device and said secondnetwork wireless access device being larger than a first pre-definedthreshold; excessive interference or noise in said first network;excessive number of unsuccessful attempts to re-associate with saidfirst network wireless access device; insufficient capacity of saidfirst network wireless access device; and transmission errors exceedinga second pre-defined threshold.

G2. The EIR terminal of G1, wherein said zero or more activecommunication sessions is provided by at least one active communicationsession including at least one message transmitted by said EIR terminal,said at least one message including decoded message data correspondingto said encoded message.G3. The EIR terminal of G1, wherein said EIR terminal configured toprovide IEEE 802.11-conformant wireless distribution system services,including association, disassociation, distribution, integration, andre-association, to said peer EIR terminals.G4. The EIR terminal of G1, wherein at least one of: said at least onehome network wireless AP, said at least one foreign network wireless APis provided by a peer EIR terminal, said peer EIR terminal said EIRterminal configured to provide IEEE 802.11-conformant wirelessdistribution system services, including association, disassociation,distribution, integration, and re-association.

While the present invention has been described with reference to anumber of specific embodiments, it will be understood that the truespirit and scope of the invention should be determined only with respectto claims that can be supported by the present specification. Further,while in numerous cases herein wherein systems and apparatuses andmethods are described as having a certain number of elements it will beunderstood that such systems, apparatuses and methods can be practicedwith fewer than the mentioned certain number of elements.

The invention claimed is:
 1. An encoded information reading (EIR)terminal, comprising: a central processing unit (CPU); and an EIR devicein communication with the CPU and configured for outputting message datacomprising decoded message data and/or raw message data; wherein the EIRdevice comprises a symbol-reading device, an RFID-reading device, and/ora card-reading device; wherein the EIR terminal is configured for:transmitting a registration request to a home agent, the registrationrequest comprising a care-of address and an authentication extension forauthenticating the EIR terminal to the home agent; and when roaming froma first network to a second network, maintaining an active communicationsession with a remote host computer using a home address for addressingthe EIR terminal when providing data of an active communication sessionacross the first network and the second network, the home addressbelonging to an associated address range of a home network.
 2. The EIRterminal of claim 1, wherein the EIR terminal is configured for, inresponse to transmitting an agent solicitation message, receiving anagent advertisement message comprising the care-of address.
 3. The EIRterminal of claim 1, wherein the active communication includes a messagetransmitted by the EIR terminal, the message comprising decoded messagedata corresponding to an encoded message.
 4. The EIR terminal of claim1, wherein at least one of the first network, the second network, andthe home network is an OSI layer 2 network.
 5. The EIR terminal of claim1, wherein the EIR terminal is configured for: detecting a roamingprocess triggering condition; and in response to a triggering condition,disassociating with the first network and associating with the secondnetwork.
 6. The EIR terminal of claim 5, wherein the roaming processtriggering condition comprises: a low receive signal strength indication(RSSI) of the first network; a difference between the first network'sRSSI and the second network's RSSI that exceeds a first pre-definedthreshold; excessive interference or noise in the first network; anexcessive number of unsuccessful attempts to re-associate with the firstnetwork; insufficient capacity of the first network; and/or transmissionerrors exceeding a second pre-defined threshold.
 7. An encodedinformation reading (EIR) terminal, comprising: a central processingunit (CPU); and an EIR device in communication with the CPU andconfigured for outputting message data comprising decoded message dataand/or raw message data; wherein the EIR device comprises asymbol-reading device, an RFID-reading device, and/or a card-readingdevice; wherein the EIR terminal is configured for: transmitting aregistration request to a home agent or a foreign agent, theregistration request comprising a care-of address and an authenticationextension for authenticating the EIR terminal to the home agent or theforeign agent, wherein the home agent has a home agent address and is incommunication with a home network and the foreign agent is incommunication with a foreign network; transmitting a registrationrequest as part of a registration request message comprising the homeaddress and the care-of address; and when roaming from a first networkto a second network, maintaining an active communication session with aremote host computer using the home address for addressing the EIRterminal when providing data of an active communication session acrossthe first network and the second network, the home address belonging toan associated address range of the home network.
 8. The EIR terminal ofclaim 7, wherein the home address and the care-of address are InternetProtocol (IP) addresses.
 9. The EIR terminal of claim 7, wherein theactive communication includes a message transmitted by the EIR terminal,the message comprising decoded message data corresponding to an encodedmessage.
 10. The EIR terminal of claim 7, wherein: the first networkcomprises a wireless access point and/or a wireless portal; and thesecond network comprises a wireless access point and/or a wirelessportal.
 11. The EIR terminal of claim 7, wherein the EIR terminal isconfigured for: detecting a roaming process triggering condition; and inresponse to a triggering condition, disassociating with the firstnetwork and associating with the second network.
 12. The EIR terminal ofclaim 11, wherein the roaming process triggering condition comprises: alow receive signal strength indication (RSSI) of the first network; adifference between the first network's RSSI and the second network'sRSSI that exceeds a first pre-defined threshold; excessive interferenceor noise in the first network; an excessive number of unsuccessfulattempts to re-associate with the first network; insufficient capacityof the first network; and/or transmission errors exceeding a secondpre-defined threshold.
 13. The EIR terminal of claim 7, wherein the EIRterminal is configured for receiving datagrams addressed to the care-ofaddress.
 14. An encoded information reading (EIR) terminal, comprising:a central processing unit (CPU); and an EIR device in communication withthe CPU and configured for outputting message data comprising decodedmessage data and/or raw message data; wherein the EIR device comprises asymbol-reading device, an RFID-reading device, and/or a card-readingdevice; wherein the EIR terminal is configured for: transmitting anagent solicitation message; receiving an agent advertisement messagecomprising a care-of address; transmitting a registration request to ahome agent, the registration request comprising the care-of address andan authentication extension for authenticating the EIR terminal to thehome agent; and when roaming from a first network to a second network,maintaining an active communication session with a remote host computerusing a home address for addressing the EIR terminal when providing dataof an active communication session across the first network and thesecond network, the home address belonging to an associated addressrange of a home network.
 15. The EIR terminal of claim 14, wherein theactive communication includes a message transmitted by the EIR terminal,the message comprising decoded message data corresponding to an encodedmessage.
 16. The EIR terminal of claim 14, wherein at least one of thefirst network, the second network, and the home network is an OSI layer2 network.
 17. The EIR terminal of claim 14, wherein the EIR terminal isconfigured for: detecting a roaming process triggering condition; and inresponse to a triggering condition, disassociating with the firstnetwork and associating with the second network.
 18. The EIR terminal ofclaim 17, wherein the roaming process triggering condition comprises: alow receive signal strength indication (RSSI) of the first network; adifference between the first network's RSSI and the second network'sRSSI that exceeds a first pre-defined threshold; excessive interferenceor noise in the first network; an excessive number of unsuccessfulattempts to re-associate with the first network; insufficient capacityof the first network; and/or transmission errors exceeding a secondpre-defined threshold.